| 摘要 |
A metered dose dispensing valve for dispensing metered volumes of a pressurised aerosol formulation, the valve comprising a cylindrical passage or chamber (656) and a valve stem (662) movable relative to said passage or chamber (656) such that in at least some of its possible positions the valve stem (662) forms a gas-tight seal with a wall of said passage or chamber (656) by means of an annular sealing element (670,672) of resiliently deformable material located around the valve stem (662) wherein said annular sealing element (670,672) has a configuration which facilitates deformation thereof in response to forces generated during movement of said valve stem relative to the passage or chamber to reduce frictional forces and maintain a gas-tight seal. <IMAGE> |
